Revert "Submit total_alloc as monotonic count"

[ChristineTChen]

Reverts #5703.

Changing go_expvar.memstats.total_alloc to submit as monotonic_count will affect graphs on dashboards.

[codecov]

Codecov Report

Merging #5972 into master will increase coverage by 3.22%.
The diff coverage is 100%.

Impacted Files	Coverage Δ
go_expvar/tests/common.py	100% <ø> (ø)	⬆️
go_expvar/tests/test_unit.py	100% <ø> (ø)	⬆️
go_expvar/tests/test_integration.py	100% <ø> (ø)	⬆️
go_expvar/datadog_checks/go_expvar/go_expvar.py	82.44% <100%> (-0.14%)	⬇️
...ts/tooling/configuration/consumers/test_example.py
...checks_dev/tests/plugin/test_environment_runner.py
oracle/tests/test_oracle.py
...r/datadog_checks/openstack_controller/__about__.py
twistlock/datadog_checks/twistlock/twistlock.py
linkerd/datadog_checks/linkerd/linkerd.py
... and 759 more